Vocabulary acquisition is a critical part of learning a new language. Yet, due to structural, historical, and individual variability associated with natural languages, isolating the impact of specific factors on word learning can be challenging. Artificial languages are versatile tools for addressing this problem, allowing researchers to systematically manipulate properties of the language and control for learners’ past experiences. Here, we review how artificial languages have been used to study bilingual word learning, with a particular focus on the influences of language input (e.g., word properties) and language experience (e.g., bilingualism). We additionally discuss the advantages and limitations of artificial languages for bilingual research and suggest resources for researchers considering the use of artificial languages. Used and interpreted properly, artificial language studies can inform our understanding of a wide range of factors relevant to word learning.

This article reviews work that has employed artificial languages to investigate the learning and processing of additional language grammar in bilinguals, with a focus on morphosyntactic processing in sentence contexts. The article first discusses research that has utilized artificial languages to elucidate two central issues in research on bilingual third language learning and processing: the role of prior language-learning experience and cross-linguistic transfer from the native and second languages to the third. Then, research that has compared bilingual third language to monolingual second language grammar processing is discussed, with specific consideration of hypothesized bilingual advantages at language learning. Finally, future directions in artificial language learning research on bilingual morphosyntactic processing are considered.

Artificial linguistic systems can offer researchers test tube-like models of second language (L2) acquisition through which specific questions can be examined under tightly controlled conditions. This paper examines what research with artificial linguistic systems has revealed about the neural mechanisms involved in L2 grammar learning. It first considers the validity of meaningful and non-meaningful artificial linguistic systems. Then it contextualizes and synthesizes neural artificial linguistic system research related to questions about age of exposure to the L2, type of exposure, and online L2 learning mechanisms. Overall, using artificial linguistic systems seems to be an effective and productive way of developing knowledge about L2 neural processes and correlates. With further validation, artificial linguistic system paradigms may prove an important tool more generally in understanding how individuals learn new linguistic systems as they become bilingual.

Studies of statistical learning have shaped our understanding of the processes involved in the early stages of language acquisition. Many of these advances were made using experimental paradigms with artificial languages that allow for careful manipulation of the statistical regularities in the input. This article summarizes how these paradigms have begun to inform bilingualism research. We focus on two complementary goals that have emerged from studies of statistical learning in bilinguals. The first is to identify whether bilinguals differ from monolinguals in how they track distributional regularities. The second is determining how learners are capable of tracking multiple inputs, which arguably is an important facet of becoming proficient in more than one language.

Late second language (L2) learners experience pervasive difficulty mastering grammatical gender, and a comprehensive account of this deficit has yet to emerge. We investigate a previously unexamined aspect of L2 gender use: the time course of lexical feature retrieval. Using event-related potentials (ERPs) with a covert production task, we examined whether L2 gender retrieval is delayed relative to phonology and to the time course of feature retrieval in native speakers for familiar nouns whose gender participants had strong knowledge of. Results find that L2 gender retrieval is not fundamentally delayed, and that L2 lexical feature retrieval may be more susceptible to top-down influences. These findings place important constraints on accounts of L2 acquisition and processing with respect to how lexical features are represented and retrieved. Our results further suggest that deficits in online L2 gender use may stem from post-retrieval processes and/or retrieval errors rather than inherent delays in gender retrieval.

Infants develop language-specific biases favoring either consonantal or vocalic information. These phonological biases affect various levels of spoken-language recognition in children and adults. This study explored whether adults who speak a second language (L2) apply phonological biases during L2 lexical processing, and whether the biases applied are those of the native language (L1), or those appropriate for the L2. Two word reconstruction experiments were carried out in English and Mandarin Chinese. L1 and L2 speakers of English demonstrated a consonantal bias by changing English vowels faster than consonants. L1 and L2 speakers of Mandarin demonstrated a vocalic bias by changing Mandarin consonants faster than vowels. Even relatively late L2 classroom learners whose L1 triggers a consonantal bias (English) exhibited a vocalic bias in their L2 (Mandarin). Lexically related processing biases are thus determined by the phonological and lexical characteristics of the stimuli being processed and not solely by listeners’ L1.

In two lexical-decision experiments, we investigated the processing of figurative and literal meaning in idioms. Dutch native and German–Dutch bilingual speakers responded to target words presented after a minimal context idiom prime (e.g., ‘He kicked the bucket’). Target words were related to the figurative meaning of the prime (‘die’), the literal word at the end of the idiom (‘water’), or unrelated to both (‘face’). We observed facilitation in RTs for figuratively and literally related targets relative to unrelated targets for both participant groups. A higher frequency idiom-final word caused inhibition in responses to the literally related target for native speakers, indicating competition between the idiom as a whole and its literal word constituents. Native speakers further showed sensitivity to transparency of the idiom's meaning and the plausibility of the idiom as a literally interpretable sentence. The results are interpreted in terms of available L1/L2 idiom comprehension models, and a more detailed processing account for literal and idiomatic sentence interpretation.

This experimental study examined bilingual (English and another noun-dominant language) and monolingual (English) preverbal (10.5-month-old) and postverbal (12.5-month-old) infants’ word-action mapping. Sixteen infants in each group were habituated to dynamic video-displays of novel word-action pairings during infant-controlled habituation. They received two words, /wem/ and /bæf/, spoken synchronously with an adult shaking or looming an object, and were tested with switched versus same word-action pairings. Results revealed that for the preverbal bilingual infants, word-action mapping is intensified relative to postverbal bilingual infants. For the postverbal bilingual infants, word-action mapping is attenuated and inversely correlated with noun learning. No such differences were observed in the monolingual infants. These findings illustrate a perceptual protraction prior to word production, and accelerated perceptual narrowing to nouns after word production in bilingual infants learning two noun-dominant languages.

Recent findings demonstrate a bilingual advantage for voice processing in children, but the mechanism supporting this advantage is unknown. Here we examined whether a bilingual advantage for voice processing is observed in adults and, if so, if it reflects enhanced pitch perception or inhibitory control. Voice processing was assessed for monolingual and bilingual adults using an associative learning identification task and a discrimination task in English (a familiar language) and French (an unfamiliar language). Participants also completed pitch perception, flanker, and auditory Stroop tasks. Voice processing was improved for the familiar compared to the unfamiliar language and reflected individual differences in pitch perception (both tasks) and inhibitory control (identification task). However, no bilingual advantage was observed for either voice task, suggesting that the bilingual advantage for voice processing becomes attenuated during maturation, with performance in adulthood reflecting knowledge of linguistic structure in addition to general auditory and inhibitory control abilities.

In this study we examined the level of English proficiency children can obtain through out-of-school exposure in informal contexts prior to English classroom instruction. The second aim was to determine the input types that fuel children's informal language acquisition. Language learning was investigated in 780 Dutch-speaking children (aged 10–12), who were tested on their English receptive vocabulary knowledge, listening, speaking, reading and writing skills. Information about learner characteristics and out-of-school English exposure was gathered using questionnaires. The results show large language gains for a substantial number of children but also considerable individual differences. The most beneficial types of input were gaming, use of social media and speaking. These input types are interactive and multimodal and they involve language production. We also found that the various language tests largely measure the same proficiency component.

Recent research has reported superior socio-communicative skills in bilingual children. We examined the hypothesis of a bilingual pragmatic advantage by testing bilingual, bi-dialectal and monolingual children on the comprehension and processing of various pragmatic meanings: relevance, scalar, contrastive, manner implicatures, novel metaphors and irony. Pragmatic responses were slower than literal responses to control items. Furthermore, children were least accurate with metaphors and irony. Metaphors and irony were also the most difficult to process; for these meanings, pragmatic responses were slower than literal responses to the same critical items. Finally, pragmatic performance positively correlated with working memory. Despite this variation, we found no bilingual or bi-dialectal advantage over monolinguals in pragmatic responses or speed of pragmatic processing. This was also true despite bilinguals’ and bi-dialectals’ lower vocabularies as measured by formal tests. We conclude that bilingual children exhibit monolingual-like pragmatic interpretation, despite their often-reported weaker language knowledge in the target language.

Research has shown that bilinguals can perform similarly, better or poorly on verbal fluency task compared to monolinguals. Verbal fluency data for semantic (animals, fruits and vegetables, and clothing) and letter fluency (F, A, S) were collected from 25 Bengali–English bilinguals and 25 English monolinguals in English. The groups were matched for receptive vocabulary, age, education and non-verbal intelligence. We used a wide range of measures to characterize fluency performance: number of correct, fluency difference score, time-course analysis (1st RT, Sub-RT, initiation, slope), clustering, and switching. Participants completed three executive control measures tapping into inhibitory control, mental-set shifting and working memory. Differences between the groups were significant when executive control demands were higher such as number of correct responses in letter fluency, fluency difference score, Sub-RT, slope and cluster size for letter fluency, such that bilinguals outperform the monolinguals. Stroop performance correlated positively with the slope only for the bilinguals.

We report a study that investigated executive functions in four groups of participants that varied in bilingual language experience, using a task that measured two theoretically motivated mechanisms of cognitive control (proactive and reactive control). Analyses of accuracy based on aggregated measures suggested an advantage in early highly proficient bilinguals over late passive bilinguals. However, when we factored in individual variability using mixed-model regression with a full random effect structure, we only found a marginal effect of language experience. Our results emphasise the importance of including individual variability when studying bilingualism, and highlight a fundamental consideration in research on the relation between language and attention – namely, the need for a theory-driven approach to measuring cognitive control through laboratory tasks.